[quote=XxLyraxX]
So I take there will be no canon characters?
[/quote]

Sure, there can be.

[quote=RumikoOhara]
I might mention that in one of the books Harry's aunt mentions that her muggle family was so proud to find out that they had a witch in the familyI'd take that as a hint their existence isn't that secret
[/quote]

If you're talking about the first book, which is the only book I can recall her saying this, I don't think that's what she meant....

[quote=XxLyraxX]
Hmmmm....what if humans discovered the wizard world and turned hostile, frightened by that which they don't understand?
[/quote]

How would they be discovered? 

[quote=XxLyraxX]
what if there was a fight between Hogwarts and another wizarding school?
[/quote]

This seems like a good idea. Maybe they can fight Durmstrang or Beauxbatons.